Ohio Earth Science Quick Facts

Page snapshot: Ohio State Geologic Map; Fossil; 3D models; Rock; Mineral; Gem; Highest and Lowest Elevations; Places to Visit; and Additional Resources.

Image above: Ordovician-aged marine invertebrate fossils from southwestern Ohio. Photograph by Jonathan R. Hendricks.

Geologic Map of Ohio

Geologic map of Ohio showing maximum ages of mappable units. Image by Jonathan R. Hendricks for the Earth@Home project developed using QGIS and USGS data (public domain) from Fenneman and Johnson (1946) and Horton et al. (2017).

Ohio State Fossils: Trilobite and Dunkleosteus

Ohio has two official state fossils: the Ordovician trilobite Isotelus maximus and the placoderm fish Dunkleosteus terrelli.

Photograph of an Isotelus maximus trilobite fossil from the Ordovician of Ohio.

Isotelus maximus from the Ordovician of Adams County, Ohio. Photograph by James St. John (Flickr; Creative Commons Attribution 2.0 Generic license; image resized).

Isotelus plush available for sale from the Paleontological Research Institution. Order here.

Dunkleosteus skull on display at the Museum of the Earth in Ithaca, New York. Photograph by Jonathan R. Hendricks.

Dunkleosteus plush available for sale from the Paleontological Research Institution. Order here.

3D Models of fossils from Ohio

Trilobite: Flexicalymene meeki (PRI 41460) by Digital Atlas of Ancient Life on Sketchfab

Fossil trilobite Flexicalymene meeki from the Ordovician Ft. Ancient Formation of Brown County, Ohio (PRI 41460). Specimen is on display at the Museum of the Earth, Ithaca, New York. Length of specimen is approximately 3.5 cm.

Trilobite: E. crassituberculata (PRI 49388) by Digital Atlas of Ancient Life on Sketchfab

Fossil specimen of the trilobite Eldredgeops crassituberculata from the Devonian Silica Formation of Sylvania, Ohio (PRI 49388). Specimen is from the collections of the Paleontological Research Institution, Ithaca, New York. Maximum diameter of specimen is approximately 2.5 cm.

Brachiopod: Strophodonta demissa (PRI 70765) by Digital Atlas of Ancient Life on Sketchfab

Fossil specimen of the brachiopod Strophodonta demissa from the Devonian Silica Shale of Lucas County, Ohio (PRI 70765). Specimen is from the collections of the Paleontological Research Institution, Ithaca, New York. Longest dimension of specimen is approxiately 4 cm.

Treptoceras cf. duseri (PRI 45492) by Digital Atlas of Ancient Life on Sketchfab

Fossil specimen of the orthocerid cephalopod Treptoceras cf. duseri from the Ordovician Richmondian Stage of Cincinnati, Ohio (PRI 45492). Specimen is from the collections of the Paleontological Research Institution. Maximum length of specimen is approximately 17 cm.

Ohio State Rock: None

Ohio does not yet have an official state rock.

Ohio State Mineral: None

Ohio does not yet have an official state mineral.

Ohio State Gem: Ohio flint

Ohio flint is a high-quality chert found throughout eastern and central portions of the state. Native Americans used Ohio flint to make tools as early as 12,000 years ago. It is a variety of microcrystalline quartz and a favorite of lapidarists.

Photograph of a sample of blue-colored flint from Ohio.

Sample of Nellie Blue Flint from the Pennsylvanian of eastern Ohio. Photograph by James St. John (Flickr; Creative Commons Attribution 2.0 Generic license).

Ohio's Highest and Lowest Elevations

Topographic map of Ohio with physiographic regions and point of highest elevation identified. Topographic data are derived from the Shuttle Radar Topography Mission (SRTM GL3) Global 90m (SRTM_GL3) (Farr, T. G., and M. Kobrick, 2000, Shuttle Radar Topography Mission produces a wealth of data. Eos Trans. AGU, 81:583-583).